As the Optical Transport Network (OTN) gradually changes from a backbone network to the core operating network providing integrated services, the MAN as “nerve ends” of the large backbone optical networks is improved so as to provide comprehensive network services for users.
The MAN is a network that covers a city and its suburbs for providing an integrated transporting platform for metropolitan multiple services, which is generally applied in large or medium-sized cities. The MAN carries out access of voice, data, video, multimedia, Internet Protocol (IP) and the like, in basis of the multi-service optical transport network. Typically, it fulfills comprehensive protocol interworking between enterprises or individual consumers in the access network and operators in the backbone network. And, it is an integrated solution with the wide-band optical transport network as an open platform for providing multi-service transport for metropolitan applications.
The network management system of MAN requires a mature function for managing network element and network, and imposes a higher demand on carrying out large-scale, fast intelligent and end-to-end circuit configuration and realizable unified multi-service configuration and management aiming at the characteristic of large scale and multiple service types of MAN. Further, it is required to provide a management interface for an up layer network management system so that the network management system of MAN can be admitted to the integrated transport network management platform for providing a complete service support solution for co-managing large-scale network.
Presently, the MAN is principally serving as a Multi-Service Transfer Platform (MSTP) based on the Synchronous Digital Hierarchy (SDH) of optical networks, which fully utilizes the mature SDH technology and has been recognized for its abilities of performance monitor, protection switching and network management. The MAN can be reconstructed to form a Multi-Service Transport Platform primarily by mapping the multiple services into various SDH time slots in the manner of Virtual Channel (VC) concatenation or the like, and by physically integrating the SDH devices and the packet switch devices of layer 2, layer 3, or even layer 4 into a single entity.
The SDH-based MSTP has the following features that it can provide multiple physical interfaces when guaranteeing compatibility with services based on the traditional SDH network, thereby greatly reducing the cost of updating the prior SDH devices; further, it realizes to transport multiple data services with high efficiency and flexibility, because the MSTP system employs a simplified network architecture and separates the interfaces with the protocols; and it can maintain the advantages of SDH and incorporate the functions of the traditional SDH network, to effectively manage the bandwidth, thereby reducing the operation cost.
Since the service subject faced by the MAN changes from the traditional Time Division Multiplexing (TDM) voice service to various broadband services and meanwhile the client signals faced by the MAN change, since many customers request to construct a Virtual Local Area Network (VLAN) or Virtual Private Network (VPN) on layer 2 to realize resource share by various nodes of enterprises, it is required to support the data services such as Ethernet Private Line (EPL), Ethernet Virtual Private Line (EVPL) or the like. At the same time, the interface types become more and more, such as Fast Ethernet (FE), Gigabit Ethernet (GE) and Enterprise System Connection (ESCON).
Since the traditional MAN management system can merely manage the SDH services, it is highly required for the network management to support the data service management due to the change of the service subject of the MAN, so as to conveniently provide data services in the MAN and to facilitate a complete compatibility of voice service and data service within the system.
Therefore, the prior MAN management method directs to the SDH service only and the service model simply includes an SDH VC model that is formed by a path trail and trail termination points at two ends, while there is no model for other data services. As a result, it cannot carry out the network management for data services.